Psychobiologische Mechanismen bei der Pathophysiologie chronischer viszeraler Schmerzen

A review of neuroendocrine immune system abnormalities in IBS based on the brain–gut axis and research progress of acupuncture intervention

Irritable bowel syndrome (IBS) is a common digestive disorder observed in clinics. Current studies suggest that the pathogenesis of the disease is closely related to abnormal brain–gut interactions, hypokinesia, visceral sensory hypersensitivity in the gastrointestinal tract, and alterations in the intestinal microenvironment. However, it is difficult for a single factor to explain the heterogeneity of symptoms. The Rome IV criteria emphasized the holistic biologic-psycho-social model of IBS, suggesting that symptoms of the disease are closely related to neurogastroenterology and various abnormalities in brain–gut interaction. This study comprehensively reviewed the relationship between the brain–gut axis and IBS, the structure of the brain–gut axis, and the relationship between the brain–gut axis and intestinal microenvironment, and discussed the relationship between the abnormal regulation of the nervous system, endocrine system, and immune system and the incidence of IBS on the basis of brain–gut axis. In terms of treatment, acupuncture therapy can regulate the neuroendocrine-immune system of the body and improve the intestinal microenvironment, and it has the advantages of safety, economy, and effectiveness. We study the pathogenesis of IBS from local to global and micro to macro, and review the use of acupuncture to treat the disease as a whole so as to provide new ideas for the treatment of the disease.

[Psychosocial factors in pain and pain management : A statement]

Although psychosocial factors have a profound impact on the experience of pain and pain recovery, the transfer to clinical application has so far been insufficient. With this article, a task force of the special interest group "Psychosocial Aspects of Pain" of the German Pain Society (Deutsche Schmerzgesellschaft e. V.) would like to draw attention to the considerable discrepancy between existing scientific evidence on the importance of psychosocial factors in the development of chronic pain disorders and the translation of these findings into the care of pain patients. Our objective is a stronger integration of psychological and psychosomatic expertise in pain treatment and research, as well as the improvement of structural and institutional conditions, to achieve an increased consideration of psychosocial aspects. In this way, modern, integrative and complex pain concepts can reach the patient. Based on these fundamental findings on the importance of psychosocial factors in pain and pain treatment, implications for the transfer to clinic and further research will be shown.

Changing Beliefs About Emotions in IBS: A Single Case Design

BACKGROUND

Previous research suggests benefits of targeting beliefs about the unacceptability of emotions in treatment for irritable bowel syndrome (IBS).

AIMS

The current study developed and tested an intervention focusing on beliefs and behaviours around emotional expression.

METHOD

Four participants with IBS attended five group sessions using cognitive behavioural techniques focusing on beliefs about the unacceptability of expressing emotions. Bi-weekly questionnaires were completed and a group interview was conducted. This study used an AB design with four participants.

RESULTS

Averages indicate that participants showed decreases in beliefs about unacceptability of emotions and emotional suppression during the intervention, although this was not reflected in any of the individual trends in Beliefs about Emotions Scale scores and was significant in only one individual case for Courtauld Emotional Control Scale scores. Affective distress and quality of life improved during follow-up, with only one participant not improving with regard to distress. Qualitative data suggest that participants felt that the intervention was beneficial, referencing the value in sharing their emotions.

CONCLUSIONS

This study suggests the potential for beliefs about emotions and emotional suppression to be addressed in cognitive behavioural interventions in IBS. That beliefs and behaviours improved before outcomes suggests they may be important processes to investigate in treatment for IBS.

Small-Conductance Ca2+-Activated K+ Channel 2 in the Dorsal Horn of Spinal Cord Participates in Visceral Hypersensitivity in Rats

Visceral hypersensitivity is a highly complex and subjective phenomenon associated with multiple levels of the nervous system and a wide range of neurotransmission. The dorsal horn (DH) in spinal cord relays the peripheral sensory information into the brain. Small conductance Ca²⁺-activated K⁺ (SK) channels regulate neuronal excitability and firing by allowing K⁺ to efflux in response to increase in the intracellular Ca²⁺ level. In this study, we examined the influence of SK2 channels in the spinal DH on the pathogenesis of visceral hypersensitivity induced by colorectal distension (CRD) in rats. Electrophysiological results showed that rats with visceral hypersensitivity presented a decrease in the SK channel-mediated afterhyperpolarization current (I_AHP), and an increase in neuronal firing rates and c-Fos positive staining in the spinal DH. Western blot data revealed a decrease in the SK2 channel protein in the membrane fraction. Moreover, intrathecal administration of the SK2 channel activator 1-EBIO or CyPPA alleviated visceral hypersensitivity, reversed the decrease in I_AHP and the increase in neuronal firing rates in spinal DH in rats that experienced CRD. 1-EBIO or CyPPA effect could be prevented by SK2 channel blocker apamin. CRD induced an increase in c-Fos protein expression in the spinal DH, which was prevented by 1-EBIO. Together, these data suggest that visceral hypersensitivity and pain is associated with a decrease in the number and function of membrane SK2 channels in the spinal DH. Pharmacological manipulation of SK2 channels may open a new avenue for the treatment of visceral hypersensitivity and pain.

Highlights:-

Neonatal colorectal distension induced visceral hypersensitivity in rats.

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Visceral hypersensitivity rats presented a decrease in afterhyperpolarization current (I_AHP) and membrane SK2 channel protein in the spinal dorsal horn.

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Visceral hypersensitivity rats presented an increase in neuronal firing rate in the spinal dorsal horn.

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Intrathecal administration of SK2 channel activator 1-EBIO or CyPPA prevented visceral hypersensitivity and decrease in I_AHP.

Heart rate variability characteristics of patients with irritable bowel syndrome and associations with symptoms

BACKGROUND

Disturbed brain-gut interactions are assumed to be of importance for symptom generation in patients with irritable bowel syndrome (IBS). The autonomic nervous system (ANS) is part of the bidirectional brain-gut communication, but previous studies in IBS show diverging results. We aimed to identify subgroups of IBS patients with distinct ANS characteristics differentiating them from healthy controls (HC), and to study associations between ANS status and symptoms.

METHODS

Heart rate variability (HRV) was measured in IBS patients and HC (Holter monitoring: supine and standing positions with controlled respiration and ambulatory 24-hour period). Frequency (5 minutes, supine, standing) and time domains (24 hours, day, night) were analyzed. Validated questionnaires were used to measure gastrointestinal and psychological symptoms in patients. Patients and HC were compared on a univariate and multivariate level (principal component analysis [PCA] and orthogonal partial least squares discriminatory analysis (OPLS-DA)).

KEY RESULTS

We analyzed 158 IBS patients (Rome III) and 39 HC. Patients differed significantly from HC in HRV parameters during daytime and in standing position. In the PCA, a majority of patients overlapped with HC, but the weighted means differed (P < .01). A subset of patients (n = 30; 19%) with an aberrant global HRV profile was identified through PCA and OPLS-DA; these patients reported more severe symptoms of frequent (P < .05) and loose stools (P = .03), as well as urgency (P = .01).

CONCLUSIONS AND INFERENCES

Altered ANS function was demonstrated in patients with IBS, and this might be of particular relevance for symptoms in a subset of the patients.

Interoceptive awareness and its relationship to hippocampal dependent processes

Many neuropsychological and animal lesion studies point to the hippocampus as being critical for mediating interoceptive awareness, while neuroimaging studies have been used to argue for the importance of the insula and anterior cingulate cortex. Here, using healthy young adults - as with the neuroimaging data - we tested for an association between performance on a hippocampal dependent learning and memory (HDLM) measure (logical memory percent retention) and interoceptive awareness assessed on three tasks - heart rate tracking, water loading and the Multidimensional Assessment of Interoceptive Awareness questionnaire (MAIA). After controlling for other relevant potentially confounding variables, we found significant associations between both the water loading and MAIA measures (which were both correlated) and HDLM performance. These findings imply that hippocampal dependent processes are involved in interoceptive awareness in healthy young adults. More tentatively, they suggest that medial temporal lobe structures may mediate interoceptive tasks that involve ingestion and/or integration of past and current state-based information.